Scientists have unearthed thick and massive deposits of ice in some regions on Mars. The images taken by the High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA’s Mars Reconnaissance Orbiter (MRO) showed the three-dimensional structure of massive ice deposits on Mars. The ice sheets extend from just below the surface to a depth of 100 meters or more and appear to contain distinct layers.

It extending downward from depths as shallow as 1 to 2 meters below the surface, which could preserve a record of Mars’ past climate, the researchers noted in the journal Science. “We expect the vertical structure of Martian ice-rich deposits to preserve a record of ice deposition and past climate,” said Colin M. Dundas, from the US Geological Survey.

“They might even be a useful source of water for future human exploration of the red planet,” Dundas added. The researchers investigated eight locations on Mars and found thick deposits cover broad regions of the Martian mid-latitudes with a smooth mantle. However, erosion in these regions creates scarps that expose the internal structure of the mantle.

The scarps are actively retreating because of sublimation of the exposed water ice. The ice deposits likely originated as snowfall during Mars’ high-obliquity periods and have now compacted into massive, fractured, and layered ice. Previous researchers have revealed that the Red Planet harbors subsurface water ice. Recent observations by MRO’s ground-penetrating Shallow Radar instrument revealed a buried ice layer that covers more ground than the state of New Mexico.

NASA’s Phoenix lander had also dug up some ice near the Martian north pole in 2008, however, it is not clear if that is part of the big sheet.